1. Field of the Invention
Embodiments of the invention generally relate to electronic device fabrication, such as for photovoltaic or semiconductor devices, and more particularly to thin films and the methods for forming such films, such as by epitaxial lift off (ELO) techniques.
2. Description of the Related Art
A critical phase of electronic device fabrication involves handling and packaging of thin films which are used in the solar and semiconductor industries. These devices may be manufactured by depositing an epitaxial layer on a sacrificial layer on a growth substrate, then etching the sacrificial layer to separate the epitaxial layer from the growth substrate. This technique is known as epitaxial lift off (ELO) and the thin epitaxial layer is known as an ELO thin film. These thin films are typically used as a photovoltaic cell, a laser diode, a semiconductor device, or another type of electronic device. The thin epitaxial film is very difficult to handle, bond to a substrate, and to package since each film is very fragile (e.g., crack under very small forces) and has extremely narrow dimensions (e.g., difficult to align).
Also, the ELO process has always been a cost prohibiting technique for commercially producing the thin film devices. Current ELO processes include transferring a single growth substrate through many fabrication steps while producing a single thin film. The current processes are time consuming, costly, and rarely produce commercial quality thin films.
Therefore, there is a need for more robust ELO thin film materials and methods for forming such materials wherein the methods are less time consuming and less expensive than known processes.